Apparatus for automatically electroplating various articles with chromium



Feb. 4, 1969 KAZUYA HOJYO APPARATUS FOR AUTOMATICALLY ELECTROPLATINGVARIOUS ARTICLES WITH CHROMIUM Sheet Filed July 27, 1965 FIGT [lllllllHlllHllllll m r T N P ma M 8 1 M x l WV W o K V? Y o V 5 B 2 1 7 4 J r 4w.

3,425,926 OPLATING IUM KAZUYA HOJYO APPARATUS FOR AUTOMATICALLY ELECTRVARIOUS ARTICLES WITH CHROM Feb. 4. 1969 Fil ed July 27. 1965 Sheet m ag i\ INVENTOR.

United States Patent Claims ABSTRACT OF THE DISCLOSURE An automaticelectroplating apparatus for various small articles comprising at leastone electrolytic tank having an outer wall constituting a cathode andvertically oriented defining a vertical tank axis; an anode memberdisposed within each of the at least one electrolytic tank and spacedfrom the walls defining an article receiving region therebetween, meansfor orbiting the at least one electrolytic tank in a circular orbitabout a central vertical axis parallel to and spaced from the verticaltank axis, for generating a centrifugal force on the articles in thearticle region causing the articles to press against the outer wall andthe at least one electrolytic tank, and means for individually revolvingeach of the at least one electrolytic tank about its vertical tank axiswhereby the articles are uniformly and evenly coated by movement on theouter wall of the tank due to its movement relative thereto.

The present invention relates to an apparatus for automaticallyelectroplating various articles with chromium, in general, and to anapparatus for automatically electroplating with chromium byadvantageously utilizing centrifugal force which is generated when aphysical solid makes a circular motion of a certain angular velocity.

A chromium plating electrolytic tank according to the present inventionrevolves in an orbit of the above-mentioned circular motion, while thetank itself rotates sufficiently slow so as not to impede thecentrifugal force generated by its revolution, so that the articleswhich are placed into the tank to be electroplated with chromium arepressed against the wall of the tank to automatically form a uniformfilm of chromium on their surfaces.

Heretofore various methods of electroplating a large quantity of smallarticles with chromium with the aid of a basket, a net or a barrel havebeen utilized. However, these methods have several shortcomings becausein these methods the plated articles are pressed against the negativepole only by gravity. For instance, because of variations in the densityof electrolyte, the gravity force on the articles to be plated and thelike, there is every probability that the plating film on their surfaceis substantially lacking in uniformity. Consequently highly special careof the electrolyte and advanced plating techniques and skill arerequired in these methods. In addition, these methods are notsatisfactory from the standpoint of productivity of labor required inthese methods. Consequently the automation of electroplating withchromium is in the last analysis dependent upon the means of making thearticles press closely against the negative pole.

In view of the above-mentioned shortcomings of the conventional methods,it is an object of the present invention and it has been conceived as aresult of various investigations, that such shortcomings can be overcomeby utilizing centrifugal force and to provide an apparatus in accordancewith the present invention, capable of automatically electroplating,with chromium, a larger quantity of small articles in a short time.

It is another object of the present invention to provide an automaticelectrolytic apparatus for various small arti- 3,425,926 Patented Feb.4, 1969 cles comprising an electrolytic tank and an inner wall membertherein between which the articles are received and means for orbitingthe tank about a central vertical axis and means for rotating the tankabout its own axis whereby the articles are uniformly and evenlyactuated.

With these and other objects in view which will become apparent in thefollowing detailed description. the present invention will be clearlyunderstood in connection with the accompanying drawings, in which:

FIGURE 1 is an elevation of the apparatus designed in accordance withthe present invention with a portion in vertical section;

FIG. 2 is an enlargement of the vertical section of FIG. 1; and

FIG. 3 is the schematic plan view of the apparatus.

Referring now to the drawings and in particular to FIG. 1, a bearingpart 2 is provided vertically in the center of a base 1 and a shaft 3 isaxially supported by the bearing part 2. On the upper end of the shaft3, a table 4 is fixed having a horizontal surface. When the shaft 3 isrotated within the bearing part 2 by means of an electric motor (notillustrated), the table 4 provided over the base 1 will undergo acircular motion at a certain speed.

Above the table 4 is eccentrically provided chromium platingelectrolytic tanks 5 through the intermediary of a bearing 6, so thatthe tanks 5 can revolve around the shaft 3 due to the above-mentionedcircular motion of the table 4.

The tank 5 comprises a cylinder with its lower part tapering off to theend. It is composed of a discharge opening part 7 axially supported bythe table 4, the body of negative pole 8 and the cover part of apositive pole 9, and due to insulating packings 10, 10 interposedbetween the body of the negative pole 8, the discharge opening part 7and the cover part of the positive pole 9, these parts are insulatedfrom each other.

The cover 9 has an opening in the center, which forms an inlet port 11for the articles to be plated, and in connection with the inlet port 11a pipe part 12 hangs downwardly. In the discharge port in the lower partof the tank 5 is inserted from above in its interior, a stopper 13 forpreventing an electrolyte 25 from leaking. Two passages 14, 14 areprovided in the stopper 13 extending from its upper end to its lowerend, so that an excessive quantity of electrolyte may be dischargedtherethrough. On the upper part of the stopper 13 is preferably placed acap 16 provided with discharge ports 15, 15 of the electrolyte, so thatthe level of the electrolyte may be con trolled by moving the cap 16upwardly and downwardly. The stopper 13 can be opened by a push bar 17,which is loosely inserted into the stopper from below, pushing up thestopper. The lower end of the push bar 17 is pivotally articulated to alever 19 which is pivotally mounted on a supporting leg 18 hanging downfrom the table 4, so that the stopper may be opened and closed byswinging the lever 19. The tank 5 can be filled with the electrolyte andthe articles, together placed therein through the inlet port part 11 anddischarged through the outlet by openin g and closing the stopper 13.

In order to cause the electroplating tank 5 to rotate itself, whilerevolving around the shaft 3, a shaft 20 for turning the tank about itsown axis is disposed in the interior of the shaft 3, and firmly at theupper end of the shaft 20, to a pinion 21. The pinion 21 meshes withgears 22, 22, which are fixed around the drums of the tanks 5, 5,engaging with each other.

As the shaft 20 is run slowly by a power source other than that whichoperates the shaft 3, the tanks 5, 5 rotate individually about their ownvertical axis during their revolving orbit, due to the gearing of thepinion 21 and the gears 22, 22, at a speed which does not impede 3 thecentrifugal force generated by the revolution of the tanks.

Referring now again to the drawings, and more particularly to FIGS. 2and 3, a minus electrode 23 is brought into contact with the cathodebody 8, while the plus electrode 24 comes into contact with the anodecover 9. Screws 26 are shown as examples of articles to be plated. Aframe 27 rotates together with the table 4 and this frame serves tosupport the tank 5 at its upper part so as to prevent the latter fromfalling downwardly. While the tanks 5, 5, respectively revolve on thecircular orbit having the shaft 3 as their center and simultaneouslyrotate individually slowly centering around their axis at their movingposition on the orbit, the revolving or orbiting speed of the tanks 5, 5is greater than their individual axis rotating speed. As a result, bythe action of the centrifugal force centering around the shaft 3, theelectrolyte 25 forms a vertical surface upon the orbit side most remotefrom the shaft 3 and having the larges radius. It is preferable to forma bowl-shaped sloping part from the bottom surface of the tank 5 up toits side wall. As shown in FIGURE 1, the articles 26 such as, forinstance, the screws having diameters ranging for example, from 1 mm. tomm. and which fill the bottom part of the tank 5, slide up the slopingpart by the action of the centrifugal force, so that they closely pressagainst the pipe wall of the cathode body 8.

The electric current flows in the electrolyte 25 which contacts bothelectrodes of the anode cover part 9 and the cathode body 8 and, by thestrong close adherence of the articles 26 to the cathode body 8, thechromium in the electrolyte can be separated upon the surface of thearticles 26.

Since the articles to be plated by the automatic chromium electroplatingapparatus according to the present invention are pressed stronglyagainst the surface of the cathode by the action of the centrifugalforce, the contact of the articles with the cathode can be steadilymaintained and there is no need of hanging up the articles as in theconventional methods, so that a large quantity of the articles can beplated most efficiently. In addition, inasmuch as the articlesthemselves rotate on their revolving orbit at a slow speed so as not toimpede the centrifugal force generated by their revolution, the articlescan be stirred up inside the tanks respectively, so that a uniformplating film is formed upon the surface of the articles.

I claim:

1. An automatic electrolytic apparatus for various small articlescomprising at least one electrolytic tank including an outer member andvertically oriented defining a vertical tank axis,

an inner member disposed within said at least one electrolytic tankspaced from said outer member defining an article receiving regiontherebetween for said various small articles,

one of said members constituting an anode, the other of said membersconstituting a cathode, means for orbiting said at least oneelectrolytic tank in a circular or-bit about a central vertical axisparallel to and spaced from said vertical tank axis for generating acentrifugal force on said articles in said article receiving regioncausing said articles to press against said outer member of saidelectrolytic tank, and means for individually revolving each of said atleast one electrolytic tank about its vertical tank axis whereby saidarticles can be uniformly and evenly coated by movement on said outermember of said electrolytic tank due to its movement relative thereto.

2. The apparatus, as set forth in claim 1, wherein said outer member issaid cathode, and

said inner member is said anode.

3. The apparatus, as set forth in claim 2, wherein said articlereceiving region is adapted to receive an electrolyte containingchromium, whereby chromium is uniformly and evenly plated on saidarticles.

4. The apparatus, as set forth in claim 2, wherein said outer member issubstantially cylindrical.

5. The apparatus, as set forth in claim 4, wherein said outer member hasa frustoconical bottom.

6. The apparatus, as set forth in claim 2, wherein said inner member isa cylindrical pipe.

7. The apparatus, as set forth in claim 6, wherein said outer memberdefines a central discharge port at the bottom thereof,

a stopper member releasably disposed in said discharge port,

a tubular cap closed at one end and vertically slidably disposed againstsaid stopper member,

said stopper member having passages extending substantially verticallyand therethrough, and

said cap having discharge ports formed on the sides thereof in liquidcommunication with said passages for controlling the level ofelectrolyte.

8. The apparatus, as set forth in claim 1, wherein said means fororbiting comprises,

a base having a bearing part,

a shaft rotatably mounted in said bearing part and defining said centralvertical axis,

a table having a horizontal surface fixed to an upper end portion ofsaid shaft,

means for supporting said at least one electrolytic tank on said tablespaced from said central vertical axis, and

means for turning said shaft.

9. The apparatus, as set forth in claim 8, wherein said shaft is ahollow shaft,

said means for individually revolving each of said at least oneelectrolytic tank comprising, an inner shaft provided inside said hollowshaft and rotatably disposed relative said hollow shaft for independentrotation,

a pinion fixed to the upper portion of said inner shaft,

said means for supporting said at least one electrolytic tank on saidtable constituting a rotatable bearing support,

circular gear means secured to said at least one electrolytic tank andmeshing with said pinion, and

means for turning said inner shaft.

10. The apparatus, as set forth in claim 1, wherein said means fororbiting said at least one electrolytic tank and said means forindividually revolving each of said at least one electrolytic tankcooperatively adapted such that said revolving is at a speed which doesnot impede said centrifugal force generated by said orbiting.

References Cited UNITED STATES PATENTS 1,530,614 3/1925 Pleister 118-53XR 892,417 7/1908 Glover 204201 895,164 8/1908 Cowper-Coles 2041991,520,676 12/1924 Koppin 204-200 1,525,432 2/1925 Adam et a1 204201 XR1,669,430 5/1928 Thayer 204213 XR 1,782,614 11/1930 Hollins 2041992,721,837 10/1955 Backer 204201 2,865,831 12/1958 Ransohoff 2042133,359,195 12/1967 Hojyo 204--212 FOREIGN PATENTS 496,217 1950 France.

6,403,667 10/ 1964 Netherlands.

0 JOHN H. MACK, Primary Examiner.

W. VAN SISE, Assistant Examiner.

US. Cl. X.R.

